The present disclosure relates to a differential of a motor vehicle, in particular an axle differential of a passenger vehicle, having an input member, via which the drive power is introduced into the axle differential, and two output members, via which the drive power is transmitted to power consumers, and having a differential unit which acts in a positive-locking manner and which is arranged between an input member and output members and which has differential members of a differential mechanism, and via which the drive power can be transmitted from the input member in a branched manner to the output members with a differential speed being allowed between the output members.
Such axle differentials are generally known in the prior art and are an object of substantially each motor vehicle. They are used in particular to compensate for the differential speeds of a driven wheel on the inner side of a bend and the driven wheel at the outer side of a bend of the same axle during travel round bends.
In cases in which the drive train of a motor vehicle has a permanently driven primary drive train, to which a secondary drive train can be connected in order to produce all-wheel drive (sometimes referred to as a hang-on all-wheel concept), it may be advantageous to completely decouple the secondary drive train components from the primary drive train when the secondary drive train is not driven and to stop them, that is to say, to decouple them both from the primary drive train and from the secondary drive wheels. Power losses, in particular drag losses, in the disconnected, stopped secondary drive train, which can otherwise be caused by friction losses (toothed wheels in engagement, occurrences of bearing friction), by splash losses (components which are introduced into oil reservoirs) or by additional rotational acceleration requirement, when the secondary drive train components are dragged during travel by the wheels of the secondary drive train which roll on the road, are thereby prevented. The secondary drive train components which may advantageously be intended to be stopped may also include components of an axle differential which is provided in the secondary drive train.
Such a drive concept is disclosed in EP2419036 A2 in the case of use of a compensation unit which does not operate in a positive-locking manner and in which furthermore a synchronization device having a braking device is provided in the region of a PTU (Power Take-Off Unit), via which device not only can the secondary drive train be decoupled from the primary drive train, but in addition it is also ensured that the components of the switched-off secondary drive train can be completely stopped. As a result of the arrangement of the synchronization device and the braking device on the PTU, however, those components act in a remote manner from the components which form the substantial mass of the components to be stopped. The mapping of that synchronization and braking function in the entire brake train is thereby not very compact and the forces which are intended to be applied during the synchronization and braking operation are able to be ensured only by components of a powerful actuator system, which components have to have relatively large dimensions. This is particularly the case when the drive train does not have a differential-free, clutch-controlled compensation unit as disclosed in EP2419036 A2, but instead a conventional differential mechanism which is formed by heavy components and which operates in a positive-locking manner is provided.